1. Field of the Invention
The present invention relates to contactless identification tags in which data is read or written in a contactless manner, and more particularly to the security of information.
2. Description of Related Art
Along with the popularization of contactless identification tags in recent years with which an external device reads and writes data in a contactless manner by receiving and sending an electromagnetic wave, the awareness towards information security in connection with the contactless identification tags has grown stronger. When the owner of a contactless identification tag carries the contactless identification tag in a bag and an external device that can instruct data reading and writing operations is brought in close contact with the bag by a third person, the danger of illegal access exists. Illegal access occurs when data is illegally read from the contactless identification tag, or data is illegally written in the contactless identification tag, while the owner is unaware of such incident.
Conventionally, there exists technology to prevent illegal reading from a transponding card. The technology requires the transponding card to be stored in a special case to form a circuit that connects a power source circuit of the transponding card to a grounding through a resistor such that no electric power is induced with an electromagnetic wave call. Also, there exists a technology to disable responses of a radio type information storage medium by housing the radio type information storage medium in a special case that is formed from a conductive material to thereby shut off an electromagnetic wave.
However, in both of these technologies described above, in order to prevent illegal accesses to a contactless identification tag by a third person other than the owner of the contactless identification tag, the owner needs to consciously perform certain tasks such as storing the contactless identification tag in the special case. In this situation, each time the contactless identification tag is used, it needs to be taken out from the special case. This is tedious. Also, the special case does not provide sufficient prevention against illegal access, because there is a possibility the special case is lost, and there is also a possibility to forget to store the card in the special case.
The present invention is made to solve the problems described above, and an advantage is to provide a contactless identification tag that readily enables secure prevention against illegal access without adding a special device for preventing illegal access.